1. Field of the Invention
This invention relates to the field of packet telephony, and in particular, for translating telephone calls between dissimilar networks, such as dissimilar packet switched networks or such as the translation of legacy telephone calls on the public switched telephone network into packets for transmission on packet networks, e.g., IP networks.
2. Description of the Background
With the development and proliferation of packet (IP and ATM) networks, there has arisen an opportunity of further deploying or communicating traditional telephone calls traditionally being communicated over the public switched telephone network (PSTN) as voice over packet (Voice over IP or Voice over ATM) communication on traditional data networks.
In such environments, when it is desired to translate between two or more networks, there is typically provided a gateway between the networks which translates the format of the voice, fax or data between the formats used in each of the networks.
Functionally the gateway must be capable of the following:                a. Terminate packet data;        b. Terminate circuit switched data;        c. Provide required media processing to translate between dissimilar networks including voice transcode, echo cancellation, tone detection and generation, tone relay over packet network, FAX relay, data format transcode;        d. Handle call establishment using circuit switched signaling protocols such as ISDN, SS7;        e. Enable commissioning and management of system from management console; and        f. Provide a control interface enabling control over call establishment and data routing through the system.        
Gateways are normally constructed using a number of specialized processors with dedicated software to carry out the various functions outlined above. Processors typically used include Digital Signal Processors (DSPs), Network Processors (NPs) and Embedded Control Processors. The architecture is generally closed and there is a tight coupling between the processors used, their layout and interconnect, and the software running on each processor.
In the construction of a packet telephony gateway, it is common for a gateway manufacturer to license software components from a number of independent software suppliers. The software is typically targeted to a single processor or small selection of processors. Further, the software will typically impose constraints on how the processors are connected. Lastly, the software is typically “closed” and does not allow the gateway manufacturer to customize or extend the software for his own particular system.
In accordance with the invention described herein, there is provided a silicon platform independent gateway solution, realized using software that presents a number of Application Programmer Interfaces (APIs), enabling the easy customization and/or extension of the software system. Thus, the problems involved with the current solutions are avoided and a highly flexible solution is provided.